/* Copyright (c) 2005-2021 Jay Berkenbilt
 * Copyright (c) 2022-2025 Jay Berkenbilt and Manfred Holger
 *
 * This file is part of qpdf.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 *
 * Versions of qpdf prior to version 7 were released under the terms of version 2.0 of the Artistic
 * License. At your option, you may continue to consider qpdf to be licensed under those terms.
 * Please see the manual for additional information.
 */

#ifndef QPDFLOGGER_H
#define QPDFLOGGER_H

/*
 * This file provides a C API for QPDFLogger. See QPDFLogger.hh for information about the logger and
 * examples/qpdfjob-c-save-attachment.c for an example.
 */

#include <qpdf/DLL.h>
#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif

    /* To operate on a logger, you need a handle to it. call qpdflogger_default_logger to get a
     * handle for the default logger. There are functions in qpdf-c.h and qpdfjob-c.h that also take
     * or return logger handles. When you're done with the logger handler, call qpdflogger_cleanup.
     * This cleans up the handle but leaves the underlying log object intact. (It uses a shared
     * pointer and will be cleaned up automatically when it is no longer in use.) That means you can
     * create a logger with qpdflogger_create(), pass the logger handle to a function in qpdf-c.h or
     * qpdfjob-c.h, and then clean it up, subject to constraints imposed by the other function.
     */

    typedef struct _qpdflogger_handle* qpdflogger_handle;
    QPDF_DLL
    qpdflogger_handle qpdflogger_default_logger();

    /* Calling cleanup on the handle returned by qpdflogger_create destroys the handle but not the
     * underlying logger. See comments above.
     */
    QPDF_DLL
    qpdflogger_handle qpdflogger_create();

    QPDF_DLL
    void qpdflogger_cleanup(qpdflogger_handle* l);

    enum qpdf_log_dest_e {
        qpdf_log_dest_default = 0,
        qpdf_log_dest_stdout = 1,
        qpdf_log_dest_stderr = 2,
        qpdf_log_dest_discard = 3,
        qpdf_log_dest_custom = 4,
    };

    /* Function should return 0 on success. */
    typedef int (*qpdf_log_fn_t)(char const* data, size_t len, void* udata);

    QPDF_DLL
    void qpdflogger_set_info(
        qpdflogger_handle l, enum qpdf_log_dest_e dest, qpdf_log_fn_t fn, void* udata);
    QPDF_DLL
    void qpdflogger_set_warn(
        qpdflogger_handle l, enum qpdf_log_dest_e dest, qpdf_log_fn_t fn, void* udata);
    QPDF_DLL
    void qpdflogger_set_error(
        qpdflogger_handle l, enum qpdf_log_dest_e dest, qpdf_log_fn_t fn, void* udata);

    /* A non-zero value for only_if_not_set means that the save pipeline will only be changed if it
     * is not already set.
     */
    QPDF_DLL
    void qpdflogger_set_save(
        qpdflogger_handle l,
        enum qpdf_log_dest_e dest,
        qpdf_log_fn_t fn,
        void* udata,
        int only_if_not_set);
    QPDF_DLL
    void qpdflogger_save_to_standard_output(qpdflogger_handle l, int only_if_not_set);

    /* For testing */
    QPDF_DLL
    int qpdflogger_equal(qpdflogger_handle l1, qpdflogger_handle l2);

#ifdef __cplusplus
}
#endif

#endif // QPDFLOGGER_H